Temperature-indicating device



'Aug. 5, 1930. E, FONSECA 1,772,279

TEMPERATURE INDICATING DEVICE Filed April 10, 1929 X g IMIIIHIIHHI lnl ul m ATTORNEYS Patented Aug. 5, 1930 UNITED STATES PATENT OFFICE EDWARD L. FONSECA, OF NEWARK, NEW JERSEY, ASSIGNOR Tb THE WILCOLATOR COMPANY, OF NEWARK, NEW JERSEY, A CORPORATION OF DELAWARE TEMPERATURE-INDICATING DEVICE Application filed April 10, 1929.

This invention relates to thermostatic indicating devices of the type in which a temperatare-responsive element exposed to vary ng temperatures operates to control indicating means at a remote point. More particularly, the invention is concerned with a device which includes electric lamps which provide the desired temperature indication, the thermostatic element operating a switch by which the lamp circuits are COIltI'OllQdTThG device of the invention is especially adapted for use on a motor car to provide indications as to engine temperature at a point easily visible to the driver, and an embodiment of the invention suitable for that purpose will be described by way of exam' le, though it is to be understood that the utility of the device is not,- limited to that particular application.

In a device ofthis type for use on an automobile, it is not necessary that the driver should be given an indication of the exact temperature of the motor, since there IS a substantial range of temperature within whlch the motor operates safely and efhciently. \Vhen the motor temperature exceeds a certain upper limit, then there exists a dangerous condition, due, for instance, to insufficient water or oil, a faulty water ump, or the like, which requires correction. owever, so long as the engine works at a temperature below this limit, it is ordinarily unimportant what the exact temperature is, and that temperature may vary considerably with changes in air temperature, speed of motor, etc. i

The device of the present invention is accordingly constructed to include an indicating lamp and a circuit therefor, which lamp is lighted when the engine is running w thin the safe temperature range and another ind cating lamp with its circuit, which lamp is lighted when the engine temperature exceeds the temperature which is safe. These circuits are controlled by a switch, which is in turn 0 )erated by a thermostatic element. Preferably the thermostatic element is a b1- metall1c strip mounted in a housing which is introduced into the cooling water for the motor through a suitable opening in the water jacket, and the switch is mounted in a housmg attached to the casing for the element.

Serial No. 353,941.

This switch is of novel construction, and it includes a fixed contact and two springpressed movable contact arms, one of which bears a single contact point and the other a pair of contact points. When the motor is cold the contacts are kept apart, so that no current flows through the lamp circuits, but after the motor is started and the temperature of the cooling water passes a selected lower limit, for example, 130, the strip begins to warp, permitting the contact arm carrying the two contacts to move with it. As the temperature and the warping of the strip continues, one contact carried on the moving arm engages the contact on the other arm and a lamp is lighted within the view of the driver.

This lamp is preferably a colored lamp, and it indicates that the motor is operating under proper conditions. As the temperature rises, the two contact arms are allowed to be swung by their springs as-the strip warps until the arm having the two contacts engages the fixed contact point, whereupon the red lamp indicating a dangerous temperature is lighted. Momentarily both lamps are lighted, but as soon as the red lamp is illuminated a slight further increase in temperature causes one of the contact arms to be swung away from the other, which, results in the green lamp going out. When the red lamp alone is shining, the driver is warned that there is some condition in the motor which requires immediate attention.

. The thermostatic element and the switch constitute a small, completely enclosed unit which may be manufactured cheaply and installed without difiiculty. This device is simple in construction, and has only a few moving parts and the arrangement is such that it will operate for long periods of time without attention.

For a better understanding of the invention, reference may be had to the accompanyin%-drawings, in which ig. 1 is a plan view of the device with the cover in section, the lamp circuits being diagrammatically indicated;

gig. 2 is a transverse longitudinal section, an

Figs. 3 and 4 are views of the device with i the cover in section, showing the parts there of in positions brought about by different temperatures.

Referring now to the drawing, the device will be seen to include a switch casing made up of a circular plate 10 and a cup-shaped cover 11, the cover being secured in position by suitable screws 12 which pass through it and into the plate, and having a peripheral flange 13 into which the cover is received. Mounted on the rear face of the plate 10 is a boss 14 having an opening 15 therethrough, the outer wall of the boss bein threaded, as indicated at 16. This boss is to be threaded into an aperture in the outer wall 17 of the water jacket of the motor and to make a water-tight connection at this point, any suitable expedient may be used as, for example, a nut 18 threaded on the boss may be employed, this-nut bearing against a packing washer 19 which is interposed between the nut and the outer cylinder wall. Mounted in the end of the boss is a tube 20, which 'extends into the water space 21 asubstantial distance.

Atthe end of the tube is mounted a plug 22 which is brazed or otherwise secured in position. This plug closes the end of the tube and has a portion 23 entering the tube, in which portion is mounted in any convenient manner a bi-metallic strip 24. This strip is made of two metals having different co-efiicients of expansion, so that upon increase of temperature the strip will warp. The strip projects through the tube and the boss and through an opening 25 in the plate 10 into the interior of the casing defined by the plate and the cover, and on the end of this strip is mounted an insulating button 26 which may be made of bakelite or the like. This button projects beyond both faces of the strip and it is preferably mounted in a slot cut in the end of the strip.

Mounted on the .face of the plate 10 is a small metal plate 27 which is provided with slotted cars 28, one on each side. Threaded into the plate 10 and entering the slots in the ears are screws 29 which secure the plate 27 in position, and by loosening these screws the plate may be moved to vary the position of certain contact arms carried by it with reference to the button, the plate thus affording means for varying the temperature range within. which the device operates. On the face of the plate 27' is secured a plate 30 of insulating material, such as bakelite, and mounted in the bakelite plate are spaced posts 31 disposed near one end thereof. Each post is in electrical contact with an L-shaped plate 32 mounted on the face of the bakelite plate and having an end 33 which projects beyond the edge of the bakelite plate. In the end 33 of each plate 32 is threaded a screw 34 which serves as a binding post for a conductor.

Each post 31 carries a contact arm, the arm 35 having a straight end on which are mounted spaced contacts 36 and 37. This arm is bent around the post 31 so that the post provides a journal for the arm, the arm then terminating in a portion 38 to which is secured one end of a spring 39, the other end of the spring of which is secured to a post 39' mounted at the corner of the L-shaped plate 32. The spring 39 tends to swing the arm 35 in a counter-clockwise direction about the post 31. The arm 40 carries a single contact 41 placed in opposition to the contact 36 and this arm is acted on by a spring 12 secured at one end to the tail 13 of the arm and at the other to a post 14.

The spring tends to move the arm 40 in a* clockwise direction, the movement of the arm" being limited by a stop 45 adjacent the post 31. Each arm is held on its post by means of a washer 46, above which is a cotter pin 47 passing through the post, and the arm is spaced from the plate 30 by a washer Mounted on the plate 30 at the end opposite to that to which the posts 31 are adjacent is a plate 19 having an upward extension 50 in which is mounted a contact screw 51, this screw being in position to engage contact 37 on arm The plate 49 has an end 52 projecting beyond the edge of the plate 30 and in this end is a binding screw 53.

' The circuits for the lamps are diagrammatically illustrated in Fig. 1, a conductor 53 leading from the end 33 of the right hand plate 32 (Fig. 1) to the green lamphl. The plate 49 is connected electrically by a line 55 to the red lamp 56, while the plate 32 at the left side (Fig. 1) is connected electrically by a line 57 to one side of a source of energy illustrated at 58 as being a battery. The circuits through the red and green lamps are grounded through line 59. It is to be understood that with the construction illustrated, the green lamp is connected elec trically to the contact 11 on the arm 40, the red lamp is connected to the fixed contact 51 and one side of the source of energy is connected electrically to both contacts 36, 37

on the arm 35.

In Fig. 1, the device is shown with the parts in the position that .will be occupied when the motor cooling water is relatively cold. In this case, the free end of the strip 21 tends to bear to the left, the button 26 contacting with the arm 35 and holding this arm against the force of the spring 39 in such position that the contacts 36, 37 are disengaged from their opposing contacts. The single contact arm is forced against the stop 45 by its spring 42. In this condition of the parts, no current is flowing and both lamps are out.

\Vhen the motor is started and the water temperature begins to increase, the strip be- Ill) gins to warp and the end carrying he button begins to move to the right (Fig. 1). This movement continues until contact'36 engages contact 41 on the arm 40, and as soon as that condition exists, current from the source flows through conductor 57, plate 32, arm 35, contact 36, contact 41, arm 40, plate 32 and through the conductor53 leadin to the green lamp from which the current ows to ground. The green lamp is illuminated as soon as contacts 36 and 37 are engaged, and this indicates that the motor is operating at a safe temperature. As the temperature increases within the saferange, the thermostatic strip'with its button continues to warp toward theright and the arm continues to swing counter clockwise. The spring 39 is substantially stronger than the spring 42 so that while the button tends to move away from arm 35, the arm follows the button since spring 39 overcomes the spring 42. Eventually the arm 35 moves to a point in which the contact 37 strikes the end of the fixed contact 51, and when this occurs, a shunt circuit from the arm 35 to ground is established as follows: contact 37, contact 51, line 55, red lamp 56, conductor 59 to ground. The engagement of contact 37 with the fixed contact 51 prevents further counterclockwise movement of arm 35, butshould a further temperature increase occur, the strip will warp to carry the button 26 away from the arm 35 and into engagement with the arm 40, moving the contact on the arm away a from the contact 36. Vhen this occurs the circuit through the green lampis broken and only the red lamp is illuminated. This indi- 'cates that the dangerous temperature has begins to fall, the reverse cycle of operations takes place.

- tacts 36 and 41 engaged until the arm 35 is held against further movement.

In Fig. 4 the parts are illustrated in the positions they occupy when the dangerous temperature, for example 200, has been reached. At this point contacts 36 and41 are engaged and contact 37 on the arm 35 has come into engagement with the fixed contact 51. With the-parts in the position described, both lamps are lighted. Should the tem )erature further increase, the button 26 won d engage the arm 40 and move the arm so as to separate contact 41 from contact 36, causing the green lamp to go out.

The wiring from the switch housing, which is mounted on the engine, may be led in a suitable flexible conduit to the dash where the lamps are ordinarily mounted, the wiring passing through an opening 60 in the wall of the cover member 11. A suitable insulating bushing (not shown) may be mounted in this opening to protect the wiring and to preseparated, saidelement permitting said members to move into engagement and thereafter to move in unison as the temperature to which said element is exposed increases, and a stationary contact limiting the movement of one of said members only.

2. In a thermostatic indicating device, the combination of a pair of movable members carrying contacts, a thermostatic element normally maintaining said members with their contacts separated but acting, upon an increase in the temperature to which it is exposed, to bring about an engagement of said contacts .and a movement of said members with their contacts engaged, and a fixed contact adapted to limit the movement of one of'said members only:

3. In a thermostatic indicating device, the combination of a pair of movable members carrying contacts, a fixed contact limiting the movement of one member in one 'direction, a stop limiting the movement of the second member in the opposite direction, and thermostatic means acting upon a temperature rise to bring about a preliminary relative movementof said members to cause their contacts to engage, a secondary movement in unison, and a final movement of separation.

4. In a thermostatic indicating device, the

' combination of a pair of movable members carrying contacts, a fixed contact in the path Of movement ofone of themem'bers, a stop limiting the movement of the other member, and a thermostatic element normally engagin g the first member and holding it separated from the second member, said element on a rise of temperature bringing about a movement of said members into engagement, followed by a movement of said members in unison, said last-named moveme it being terminated by engagement of one of said members with said fixed contact, the movement of said other member continuing as the temperature rises. I

5. In a thermostatic indicating device, the combination of a pair of swinging arms carrying contacts, springs acting on the arms and tending to move them toward each other, a fixed contact in the path of movement of one of said arms, a stop limiting the movement of the second arm toward the first, and thermostatic means disposed between the arms and operable upon a rise of temperature to bring about a preliminary relative movement of said arms causing the contacts thereon to be engaged, a secondary movement of said arms in unison, and a final movement of separation of said arms.

6. In a thermostatic indicating device, the combination or a pair of swinging arms, springs tending to swing said arms toward each other, a pair of contacts mounted on one arm, a single contact mounted on the other arm, a fixed contact adapted to engage the second contact on said first arm, a stop limiting the movement of said second arm toward the first, and thermostatic means operating upon said arms and adapted upon a rise in temperature to bring about a relative movement of said arms to cause their cooperating contacts to engage, followed by a movement of said arms in unison tovbring the second contact on the first arm into engagement with the fixed contact, and a final movement of said second arm relative to the first.

7. In a thermostatic indicating device, the combination of ahousing, a pair of arms mounted within the housing and adapted to swing about spaced pivots, one of said arms being provided with a pair of contacts, the other with a single contact adapted to cooperate with one of the contacts on the first arm, a thermostatic element mounted at one end in an extension of said housing, the free ative to the first, the movement of said arms in unison being terminated by engagement" of said first arm with the fixed contact.

8. In a thermostatic indicating device, the combination of a casing, an extension from the casing, a thermostatic strip mounted within the extension and having a free end entering the casing, a pair of arms mounted to swing on spaced pivots within the casing, one arm being provided with a pair of spaced contacts, the second arm having a single contact adapted to engage with one of the contacts on said first arm, a fixed contact within the casing, springs acting on the arms and tending to move them toward each bther, these springs being of unequal strength, and a stop limiting the movement of said second arm, said thermostatic element normally engaging said first arm and maintaining it with its contacts separated from the contact 'on said second arm, said element, upon a rise in temperature, moving toward said second arm and thus bringing about a movement of the first arm toward the second and toward said fixed contact. I

9. In a thermostatic indicating device, the combination of a closed casing having an extension therefrom, a thermostatic element mounted at one end within the extension, the other end of said element lying within the casing, an insulating button carried by said element, a pair of arms mounted within the casing and adapted to swing about spaced pivots, a spring for each arm, these springs tending to move the arms into engagement, one spring being stronger than the other, a pair of contacts on the arm actuated by the stronger spring, a single contact on the second' arm, the single contact being adapted to cooperate with the pair of contacts, a fixed contact in the casing adapted to cooperate with the contact of the pair, and electrical connections to said arms, the button carried by said thermostatic element lying between said arms and normally engaging the arm having a pair of contacts.

10. In a thermostatic indicating device, the combination of an insulating plate, a pair of spaced pivots thereon, an arm mounted on each pivot for swinging movement, one of said arms carrying a pair of contacts in alignment longitudinally of said arm. the other arm carrying a single contact adapted to cooperate with the inner contact of said pair, a fixed contact disposed in position to cooperate with the outer contact of said pair, a thermostatic element having a portion movable with changesof temperature mounted adJacent said plate with said movable portion lying between said arms and adapted to engage said arms alternately, springs acting on said arms and tending to'move them toward each other, the spring acting on the arm having the pair of contacts being stronger than the other spring, the movable portion of said element normally engaging the arm with the pa r of contacts and maintaining! this arm with its contacts separated from the other contacts, the movement of said portion permitting a preliminary engagement of the contacts on the arms succeeded by engage- Itnept of the fixed contact with said outer conill) iii)

11. In a thermostatic indicating device, the combination of a pair of swinging arms mounted to swing on pivots, said arms extending in a generally parallel direction from said pivots, one arm being longer than the other, a pair of contacts disposed in longitudinal alignment on the long arm, a single contact on the other arm adapted to engage the inner contact oh the long arm, a fixed contact adapted-to engage the outer contact on the-long arm, springs tending to move said arms to bring their contacts into engagement, the spring acting on the long arm being stronger than the other spring, and a thermostatic element having a ortion adapted to move with temperature 0 ianges, said portion. lying between the arms and normally engaging the long arm and holdin it with its contacts separated from the otier contacts, the movement of said portion on an increase in temperature permitting the long arm to move to cause engagement of the I inner contact with the contact on the shortv arm followed by an engagement with the outer contact and the fixed contact, the further movement of said portioncausing the short arm to be moved away from said long arm 12. In a thermostatic indicating device, the combination of a pair of movable contacts, a stationary contact, said movable contacts being normally in engagement and one of said movable contacts being also normally in engagement with said stationary contact,

and a thermostatic element engaging said one movable contact to move the, same upon changes in temperature to successively break its engagement with said stationary contact and said other movable contact.

18. In a thermostatic indicating device, the combination of a pair of movable contacts, a stationary contact, means normally urging said movable contacts into engagement, and one of said movable contacts into engagement with said stationary contact, and a thermostatic element adapted to move said one movable contact in response to temperature changes to successively break its engagement with said stationary contact and said other movable contact.

1 L In a thermostatic indicating device, the combination of a pair of movable contacts, a stationary contact, means normally urging said. movable contacts into initial engagement, and one of said movable contacts into secondary engagement with said stationmy contact, and a thermostatic element adapted to engage said one movable element for moving the same in response to temperature changes to successively break said secondary engagement thereof with said stationary contact tien break: said initial engagement with said other movable contact.

In testimony whereof I affix my signature.

EDWARD L, FONSECA. 

